Could be. It's just an idea. Doesn't hurt to try it. When driving uphill or under a load, does the engine seem to "rattle" some from the valves? Having 93 octane will disguise this somewhat. To test this, I'd use 87 octane. If it rattles some, I'd do as mentioned, retard the timing some.
And it would get a little hot when It was just idling at lights
You mentioned that at idle, it tends to get hot or overheat? I'd check your clutch fan (if that is what you have) or flush the radiator. How old is your water pump? If your cooling system is not decipating the heat correctly, it will remain in the engine and contribute to diesling due to the heat.
No rattle under load or uphills.
And for the temp, when idling it will go up alittle but it wont get to hot and its never overheated.
What do you suggest for a topend cleaner?
Also we retimed it last spring when we replaced the cap,rotor,wires,plug,carb... and I beleve its a 9 or 10.
Whats a EGR?